Laundry and cleaning products continue to evolve to provide not only better cleaning but more benefits, such as color and fabric care and aesthetics. New agents can be developed which provide such results, but frequently in-product stability or through the wash releasability are problematic for their use. A wide variety of carrier systems and coating technologies have been developed to address these needs. Often such systems are not broadly useful.
For example, there has been a continuing search for methods and compositions which will effectively and efficiently deliver perfume from a laundry bath onto fabric surfaces. As can be seen from the art such as that referred to hereinafter, various methods of perfume delivery have been developed. U.S. Pat. No. 4,096,072, Brock et al, issued Jun. 20, 1978, teaches a method for delivering fabric conditioning agents, including perfume, through the wash and dry cycle via a fatty quaternary ammonium salt. U.S. Pat. No. 4,402,856, Schnoring et al, issued Sep. 6, 1983, teaches a microencapsulation technique which involves the formulation of a shell material which will allow for diffusion of perfume out of the capsule only at certain temperatures. U.S. Pat. No. 4,152,272, Young, issued May 1, 1979, teaches incorporating perfume into waxy particles to protect the perfume through storage in dry compositions and through the laundry process. The perfume assertedly diffuses through the wax on the fabric in the dryer. U.S. Pat. No. 5,066,419, Walley et al, issued Nov. 19, 1991, teaches perfume dispersed with a water-insoluble nonpolymeric carrier material and encapsulated in a protective shell by coating with a water-insoluble friable coating material. U.S. Pat. No. 5,094,761, Trinh et al, issued Mar. 10, 1992, teaches a perfume/cyclodextrin complex protected by clay which provides perfume benefits to at least partially wetted fabrics.
Another method for delivery of perfume in the wash cycle involves combining the perfume with an emulsifier and water- soluble polymer, forming the mixture into particles, and adding them to a laundry composition, as is described in U.S. Pat. No. 4,209,417, Whyte, issued Jun. 24, 1980; U.S. Pat. No. 4,339,356, Whyte, issued Jul. 13, 1982; and U.S. Pat. No. 3,576,760, Gould et al, issued Apr. 27, 1971.
The perfume can also be adsorbed onto a porous carrier material, such as a polymeric material, as described in U.K. Pat. Pub. 2,066,839, Bares et al, published Jul. 15, 1981. Perfumes have also been adsorbed onto a clay or zeolite material which is then admixed into particulate detergent compositions. Generally, the preferred zeolites have been Type A or 4A Zeolites with a nominal pore size of approximately 4 Angstrom units. It is now believed that with Zeolite A or 4A, the perfume is adsorbed onto the zeolite surface with relatively little of the perfume actually absorbing into the zeolite pores. While the adsorption of perfume onto zeolite or polymeric carriers may perhaps provide some improvement over the addition of neat perfume admixed with detergent compositions, industry is still searching for improvements in the length of storage time of the laundry compositions without loss of perfume characteristics, in the intensity or amount of fragrance delivered to fabrics, and in the duration of the perfume scent on the treated fabric surfaces.
Combinations of perfumes generally with larger pore size zeolites X and Y are also taught in the art. East German Patent Publication No. 248,508, published Aug. 12, 1987 relates to perfume dispensers (e.g., an air freshener) containing a faujasite-type zeolite (e.g., zeolite X and Y) loaded with perfumes. The critical molecular diameters of the perfume molecules are said to be between 2-8 Angstroms. Also, East German Patent Publication No. 137,599, published Sep. 12, 1979 teaches compositions for use in powdered washing agents to provide thermoregulated release of perfume. Zeolites A, X and Y are taught for use in these compositions. These earlier teachings are repeated in the more recently filed European applications Publication No. 535,942, published Apr. 7, 1993, and Publication No. 536,942, published Apr. 14, 1993, by Unilever PLC, and U.S. Pat. No. 5,336,665, issued Aug. 9, 1994 to Gamer-Gray et al.
Effective perfume delivery compositions are taught by WO 94/28107, published Dec. 8, 1994 by The Procter & Gamble Company. These compositions comprise zeolites having pore size of at least 6 Angstroms (e.g., Zeolite X or Y), perfume releaseably incorporated in the pores of the zeolite, and a matrix coated on the perfumed zeolite comprising a water-soluble (wash removable) composition in which the perfume is substantially insoluble, comprising from 0% to about 80%, by weight, of at least one solid polyol containing more than 3 hydroxyl moieties and from about 20% to about 100%, by weight, of a fluid diol or polyol in which the perfume is substantially insoluble and in which the solid polyol is substantially soluble.
U.S. Pat. No. 5,258,132, issued Nov. 2, 1993, and U.S. Pat. No. 5,230,822, issued Jul. 27, 1993, both to Kamel et al., relate to solid core particles encapsulated in a single coat of paraffin wax, the wax having a melting point of about 40 C. to about 50 C. and solids content of from 100 to about 35% at 40 C. and from 0 to about 15% at 50 C. This coating is said to prolong the time in which the encapsulated particles remain active in aqueous environment. U.S. Pat. No. 5,141,664, issued Aug. 25, 1992, to Corring et al., relates to cleaning compositions comprising a clear gel with opaque particles of active material uniformly dispersed and suspended in the gel. The active material is surrounded by a protective substance such as an encapsulating layer.
U.S. Pat. No. 2,809,895, issued Oct. 15, 1957 to Swisher, relates to solid essential oil containing compositions suitable for use as an ingredient of various foods, pharmaceuticals, perfumes, soaps, and cosmetics. This is said to involve forming a finely dispersed essential oil--corn syrup emulsion which is solidified and further treated to give a particulate oxidation protected essential oil product. The process is described as involving emulsifying an essential oil to which an antioxidant and dispersing agent have been added in the corn syrup solids solution, and forming a particulate solid emulsion.
In spite of such efforts, there continues to be a need for particulate delivery systems capable of incorporating a wide variety of laundry agents into laundry and cleaning compositions, especially granular detergent compositions and granular automatic dishwashing detergent compositions. Especially desirable are such particles which are stable under storage conditions of high heat and humidity. Also preferred for use are such compositions to protect water-sensitive agents from detrimental levels of water.